1. Field of the Invention
The present invention relates to finger operated spray pumps. In particular this invention relates to a spray pump that upon repeated actuation will produce a continuous discharge.
2. Description of the Prior Art
Many conventional spray pumps produce a spray which varies in pressure and volume in proportion to the force applied by the finger of the user actuating the pump. If the force applied by the finger is relatively small, the spray will not be highly atomized.
To achieve rapid atomization and the production of a high degree of atomization of the spray, double cylinder-double piston pumps, sometimes known as accumulative pressure pumps, have been developed. Such pumps usually have a dual-diameter pump chamber or body, generally the upper portion being a larger diameter than the lower portion. Separate pistons are provided in each of the different diameter portions, which pistons move together on downstroke and produce accumulation of pressure in the two chambers resulting in disengagement of the outlet valve whereby fluid is expressed through the atomizer nozzle at an instantaneously high pressure to produce fine atomization from the start of the spray until the end thereof. Accumulative pressure pumps having interconnected, different diameter pump chambers or bodies are shown in U.S. Pat. Nos. Re. 28,366; 3,746,260; 3,761,022; 3,796,375; 3,865,313; 3,907,206; 3,908,870; 3,921,861; 3,923,250; 3,940,030; 4,017,031; and 4,051,983.
In many applications it is desired to have a finger operated spray pump which will produce a continuous, extended spray even after the finger is removed from the pump in addition to the rapid and high atomization characteristic of accumulative pressure pumps. Furthermore, in some applications it is desirable to have a spray pump which will produce a continuous spray of relatively constant pressure as the spray button is repeatedly depressed and released, even though the button is not being fully depressed.
U.S. Pat. No. 3,761,022, issued to Kondo, is directed to an accumulative pressure finger operated spray pump. However, the Kondo pump does not have a continuous extended spray because when Kondo's plunger is no longer in its extreme innermost position, the outlet orifice no longer communicates with the pressurized liquid.